Last spring frost
Mar 21
Frost Dates for Powers, OR
First fall frost
Nov 14
Growing season
241 days
Hardiness zone
9a
In an average year around Powers, OR, the last spring frost (32°F) is about Mar 21 and the first fall frost is about Nov 14, giving roughly a 241-day growing season. To be safe most years, wait until Feb 16 before setting out tender plants.
Last spring frost
Dates the last frost of spring typically ends. Plant tender crops after the risk has passed for your comfort level.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | May 9 | Apr 20 | Mar 31 |
| Freeze (32°F) | Apr 12 | Mar 21 | Feb 16 |
| Hard (28°F) | Mar 18 | Feb 6 | Dec 17 |
| Severe (24°F) | Feb 12 | Jan 1 | Dec 2 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 9 | May 4 | Apr 30 | Apr 25 | Apr 20 | Apr 16 | Apr 12 | Apr 8 | Mar 31 |
| 32°F | Apr 12 | Apr 5 | Mar 31 | Mar 26 | Mar 21 | Mar 13 | Mar 4 | Feb 26 | Feb 16 |
| 28°F | Mar 18 | Mar 1 | Feb 23 | Feb 15 | Feb 6 | Jan 29 | Jan 15 | Dec 31 | Dec 17 |
| 24°F | Feb 12 | Jan 30 | Jan 15 | Jan 6 | Jan 1 | Dec 28 | Dec 21 | Dec 13 | Dec 2 |
First fall frost
Dates the first frost of fall typically arrives. Count back by a crop's days-to-maturity to know your planting cutoff.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Oct 1 | Oct 22 | Nov 14 |
| Freeze (32°F) | Oct 21 | Nov 14 | Dec 14 |
| Hard (28°F) | Nov 7 | Dec 9 | Jan 30 |
| Severe (24°F) | Nov 26 | Dec 20 | Feb 1 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 1 | Oct 9 | Oct 14 | Oct 19 | Oct 22 | Oct 27 | Oct 31 | Nov 5 | Nov 14 |
| 32°F | Oct 21 | Oct 28 | Nov 2 | Nov 9 | Nov 14 | Nov 22 | Nov 28 | Dec 3 | Dec 14 |
| 28°F | Nov 7 | Nov 17 | Nov 28 | Dec 3 | Dec 9 | Dec 16 | Dec 27 | Jan 6 | Jan 30 |
| 24°F | Nov 26 | Dec 4 | Dec 8 | Dec 14 | Dec 20 | Dec 28 | Jan 1 | Jan 11 | Feb 1 |
Growing season is measured at 32°F with about 50% probability. Hardiness zone from the 2023 USDA map; frost normals from NOAA 1991-2020.
Where this data comes from
@endif These dates are computed from the nearest official weather station with long-term records: Powers, Or, about 2.9 miles away@if(!empty($station['elevation_ft'])), at 230 ft elevation. The further the station and the greater the elevation difference from your yard, the more your local frost timing can vary.
How we calculate these dates
Frost and freeze dates come from the NOAA 1991–2020 U.S. Climate Normals, the National Oceanic and Atmospheric Administration's 30-year averages for each weather station. A date shown at the 50% level is the median: in half of years the frost falls on or before it. The 10% and 90% columns show the early and late ends of the range, so you can plant on the odds you're comfortable with. These are long-term averages, not a forecast for this year - always check your local outlook before planting.
Source: NOAA National Centers for Environmental Information, 1991–2020 Climate Normals (public domain). Harman is not affiliated with or endorsed by NOAA.
Frequently asked questions
When is the last frost in Powers, OR?
On average, the last spring frost (32°F) around Powers, OR is about Mar 21. In cooler years it can run later, so for a safer bet many gardeners wait until Feb 16.
When is the first frost in the fall?
The first fall frost around Powers, OR typically arrives about Nov 14. Count back by a crop's days to maturity to find the latest date you can plant it.
When can I plant tomatoes and other tender crops?
Tender crops like tomatoes, peppers and basil are damaged by frost, so wait until the last spring frost has passed - around Mar 21 on average, or Feb 16 to be safe most years.
How long is the growing season here?
The frost-free growing season (between the last spring and first fall 32°F frost) is about 241 days in a typical year.
Are these dates a forecast for this year?
No. They are 30-year averages from the NOAA 1991–2020 Climate Normals, not a prediction for the current year. Use them for planning and always check your local weather forecast before planting or protecting crops.
Local weather for 97466 Planting calendar → Oregon frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026